System for processing a workpiece
A wafer processing system has a moveable drain assembly having multiple drain rings. The drain rings may be spaced apart sufficiently to allow a process fluid applicator to move between them. Each drain ring provides a separate drain path, optionally in a separate recirculation loop carrying a single process fluid. The drain rings may be sequentially moved into position to collect process fluid moving off of the workpiece. As a result, process fluids may be more uniformly applied and used process fluids can be separately removed, collected, and either recycled or processed for disposal. Mixing of used process fluids is largely avoided. A lower process fluid outlet allows for processing the back side of the wafer as well, without flipping the wafer.
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The invention relates to surface preparation, cleaning, rinsing and drying of workpieces, such as semiconductor wafers, flat panel displays, rigid disk or optical media, thin film heads or other workpieces formed from a substrate on which microelectronic circuits, data storage elements or layers, micro-mechanical, micro-electro-mechanical or micro-optical elements may be formed. These and similar articles are collectively referred to herein as a “wafer” or “workpiece.”
BACKGROUND OF THE INVENTIONThe semiconductor manufacturing and related industries are constantly seeking to improve the processes and machines used to manufacture microscopic devices, such as integrated circuits. The objectives of many of these improved processes and machines include decreasing manufacturing time requirements, increasing the yield of usable devices, decreasing contamination, improving the uniformity and efficiency of manufacturing, and reducing manufacturing costs.
In the processing of wafers, it is often necessary to contact one or both sides of the wafer with a process chemical in fluid form, i.e., a liquid, vapor or gas. Such fluids, which include rinse fluids such as water, are used to, for example, etch the wafer surface, clean the wafer surface, dry the wafer surface, passivate the wafer surface, deposit films on the wafer surface, remove films or masking materials from the wafer surface, etc. Process liquids are often recirculated in a processing system, to that they may be reused multiple times. This reduces manufacturing costs since less process liquid is needed, and less waste material is created. However, when different process fluids are recirculated within the same processing chamber, there is potential for mixing between them. This is known as cross contamination. In addition to reducing the potential for cross contamination of the processing fluids, controlling how the processing fluids are applied to the wafer surfaces, and effectively cleaning or rinsing process fluids from process chamber surfaces can also often be important to the success of the processing operations. Moving and handling wafers in ways which minimize generation of contaminant particles is also often important. Current systems and methods generally have disadvantages relating to one or more of these engineering design challenges.
SUMMARY OF THE INVENTIONA new wafer processing system has now been invented that provides significant improvements in manufacturing microelectronic and similar workpieces. A moveable drain assembly having multiple drain rings greatly reduces or eliminates cross contamination of process fluids. The drain rings may be spaced apart sufficiently to allow a process fluid applicator between them. Each drain ring provides a separate drain path, optionally in a separate recirculation loop carrying a single process fluid. The drain rings may be sequentially moved into position to collect process fluid moving off of the workpiece. As a result, process fluids may be more uniformly applied and used process fluids can be separately removed, collected, and either recycled or processed for disposal. Mixing of used process fluids is largely avoided. Several different process steps each using a different process fluid can therefore be performed within a single process chamber. As a result, less process equipment workpiece handling is needed. Process performance is improved while manufacturing costs are reduced.
Other features and advantages of the invention will appear hereinafter. The features of the invention described above can be used separately or together, or in various combinations of one or more of them. The invention resides as well in sub-combinations of the features described. The process chamber can be used alone, or in a system with robotic automation and various other process chambers.
In the drawings:
In a processing system having separate drains that can be moved into position to collect a process fluid from a workpiece, the drains are spaced apart to allow a movably fluid outlet to pass between them. The separate drains, in the form of drain rings, may have a curved upper wall that deflects fluid droplets with less splattering.
As shown in
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Referring to
To adapt the processor 60 for also processing the back side of the workpiece, a lower or back side fluid supply line may connect with a fluid inlet fitting 106 on a lower nozzle assembly 102, to provide a process fluid to a lower outlet or nozzle 105. An air pipe 108 may also be used to draw in air from an inlet 110 positioned above the processor 60. The air pipe 108 leads up to a center inlet 95 in the rotor plate 92.
Turning now to
The processor 60 may be used as a stand-alone single unit, loaded and unloaded either manually or via a robot. However, more commonly, several processors 60 are provided in an automated processing system, such as the system 20 shown in
The motor 84 is switched on causing the rotor 90 to rotate. Referring momentarily to
With the drain ring assembly 65 in the position shown in
The same, or a different process fluid, may be applied to the bottom or back side of the wafer 54 through the lower nozzle 105. Accordingly, both sides of the wafer may be processed, without the need to flip the wafer over. The spinning movement of the rotor 90 creates a low pressure zone around the center of the rotor. The low pressure draws air up through the center inlet 95 from the air pipe 108. The air pipe inlet 110 is located above most or all components of the processor 60, to better avoid drawing in any particles.
Liquids on the spinning wafer move outwardly under centrifugal force. Droplets of the liquid fly off the wafer edges and are collected in the first drain ring 66. The first drain ring 66 is usually positioned with the inside surface of the curved top wall 112 slightly above, the top surface of the wafer 54. Droplets flung off from the wafer edge collide with the curved top wall 112 and are guided down along the side wall 116 to the trough formed between the lower wall or floor 114 and the side wall 116, as shown in
Referring to
In a second processing step using a different process fluid, the drain assembly lifters 120 are actuated to lift the drain ring assembly 65, from the position shown in
Referring to
The drain ring assembly 65 may have a fourth or more drain rings, to match the processor 60 with the number of process fluids used. The drain ring assembly 65 may also have only two drain rings, where only one or two process fluids are used. The design features of the drain rings described above may be used in a drain ring assembly having any number of drain rings, as well as in a single drain ring. In one example of use of a two drain ring design, a polymer removal fluid, such as ST250 is applied by a nozzle 144 with the processor as shown in
The processor 60 may optionally be set up with
As shown in
Referring to
As the rotor 180 spins at moderate to high speeds, the wafer retainer 182 pivots clock-wise (in the direction of the arrow in
The use of the singular here includes the plural, and vice versa. The use of “or” here is not exclusive. Rather “or” as used here means either one or the other, or both, and without suggesting that one is or is not an equivalent of the other. The processor described above may be modified to have a fixed drain ring assembly, and a vertically moveable rotor. The processor described above may also be used with a fixed non-rotating workpiece platform, especially when used with gas or vapor phase process fluids.
Thus, novel processors, systems, and methods have been shown and described. Various changes and substitutions may of course be made, without departing from the spirit and scope of the invention. The invention, therefore, should not be limited, except to the following claims and their equivalents.
Claims
1. Apparatus comprising:
- a rotor rotatable about a rotation axis;
- a swing arm having at least one fluid outlet, with the arm moveable to apply a fluid onto a workpiece on the rotor;
- a first drain ring generally coaxial with the rotation axis;
- a second drain ring generally coaxial with the rotation axis;
- a drain ring lifter for vertically moving the first and second drain rings;
- and with the swing arm movable horizontally from a first position outside of the drain rings, to a second position in between the first and second drain rings.
2. The apparatus of claim 1 with the first drain ring having a curved upper wall and a generally flat lower wall declining at 5-45 degree angle away from the rotation axis.
3. The apparatus of claim 1 further comprising a swing arm actuator for moving the swing arm in a back and forth movement.
4. The apparatus of claim 1 further comprising an air pipe extending up through the rotor.
5. The apparatus of claim 1 further comprising a plurality of workpiece supports each pivotably attached to the rotor, for supporting a workpiece on the rotor, while the rotor rotates with the workpiece.
6. The apparatus of claim 1 with the first drain ring attached to the drain ring lifter and with the second drain ring attached to the drain ring lifter, and with the first drain ring positioned by a fixed distance above the second drain ring.
7. The apparatus of claim 1 further comprising a shroud surrounding the drain rings.
8. The apparatus of claim 1 further comprising a third drain ring generally coaxial with the second drain ring, and with the swing arm also moveable in between the second and third drain rings.
9. The apparatus of claim 1 with the drain ring lifter comprising first and second lift assemblies positioned on substantially opposite sides of the rotor.
10. The apparatus of claim 1 further comprising a back side fluid outlet in the rotor.
11. The apparatus of claim 1 with the rotor and the swing arm vertically spaced apart by a fixed dimension.
12. The apparatus of claim 1 with the rotor supported at a fixed dimension above a base plate, and with the drain rings moveable together, vertically, relative to the base plate, to align the first or second drain ring with a workpiece on the rotor.
13. A workpiece processor, comprising:
- a rotor rotatable about a rotation axis;
- a fluid outlet in the rotor;
- a fluid source connecting to the fluid outlet in the rotor;
- a motor attached to the rotor and positioned on a first side of the rotor;
- workpiece supports on the rotor adapted to support a workpiece;
- a swing arm having at least one fluid outlet, with the arm moveable to a position over the rotor;
- a drain ring assembly including first and second drain rings generally coaxial with the rotation axis and spaced apart in fixed positions relative to each other in a direction generally parallel to the rotation axis by a dimension sufficient to allow the swing arm to move between them, and with the swing arm moveable horizontally from a first position outside of the drain ring assembly, to a second position in between the first and second drain rings, within the drain ring assembly; and
- at least one drain ring assembly lifter attached to the first and second drain rings for moving the first and second drain rings in a direction generally parallel to the rotation axis.
14. The workpiece processor of claim 13 with the drain ring assembly moveable via the drain ring assembly lifter from a first position where the first drain ring is substantially aligned in the same plane as a workpiece on the rotor, to a second position wherein the first drain ring is above the workpiece, and with the swing arm moveable between the first and second drain rings when the drain ring assembly is in the second position.
15. A workpiece processor, comprising:
- a rotor;
- workpiece supports on the rotor defining a workpiece holding position;
- at least one fluid outlet in the rotor;
- a swing arm above the rotor;
- at least one fluid outlet on or in the swing arm;
- a drain ring assembly positioned around the rotor and including first and second drain rings generally coaxial with the rotor, and vertically spaced apart from each other by a fixed distance;
- lifting means for vertically moving the drain ring assembly relative to the rotor;
- and with the swing arm movable horizontally from a first position outside of the drain ring assembly, to a second position in between the first and second drain rings, when the first drain ring is positioned above the workpiece holding position and second drain ring is positioned below the workpiece holding position.
16. The processor of claim 15 with the lifting means including a pair of linear actuators attached to the drain ring assembly.
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Type: Grant
Filed: Jan 5, 2007
Date of Patent: Dec 14, 2010
Patent Publication Number: 20080163898
Assignee: Semitool, Inc. (Kalispell, MT)
Inventor: Randy A. Harris (Kalispell, MT)
Primary Examiner: Michael Barr
Assistant Examiner: Jason Y Ko
Attorney: Perkins Coie LLP
Application Number: 11/620,508
International Classification: B08B 3/00 (20060101);